Historically, 75% of drugs have insufficient labeling to inform physicians on pediatric dosing, safety, or efficacy. Mechanisms requiring the study of new products in children are relatively new and highlight a training gap in pediatricians related t the investigation of therapeutic agents: There is an urgent need for well-trained pediatric investigators with quantitative research skills in pharmacology, epidemiology, and biostatistics. In this competitive renewal, the investigator, Daniel K. Benjamin, Jr., MD, PhD, MPH, will continue to prepare pediatricians for a career in patient-oriented research to help bridge this gap in accordance with his own long-term research goals: to improve pediatric drug development by establishing proper dosing, safety, and efficacy of drugs used in adolescents, children, toddlers, infants, and neonates. Dr. Benjamin successfully achieved the aims outlined in the original award by developing a research program in pediatric clinical pharmacology and therapeutics. The centerpiece of the program is the NICHD- sponsored Pediatric Trials Network (PTN) for which the applicant is PI and chair. The network has 27 active clinical trials and pharmacoepidemiology projects evaluating the pharmacokinetics, safety, and efficacy of 38 therapeutics. The breadth of the program is possible because the candidate successfully developed three young investigators who have secured their own NIH funding and their own mentees. In addition to offering research opportunities for the duration of the application, strengths of Dr. Benjamin's program include the unparalleled research infrastructure of the world's largest academic research organization, Duke Clinical Research Institute, and a longstanding academic partnership with the renowned University of North Carolina School of Pharmacy. Through this integral partnership, Dr. Benjamin has developed an NIH-sponsored fellowship training program and a pathway for pediatricians to secure PhD- level training in clinical pharmacology and pharmacoepidemiology. In this competitive renewal, the applicant seeks to continue using the PTN as a platform for mentorship of young investigators from both within and outside Duke University. Trainees in clinical pharmacology across the US will be recruited to lead network research projects. Specifically, the proposed Antimicrobial Cerebrospinal Fluid Pharmacokinetics in High-Risk Infants PTN study will offer mentees the opportunity to capitilize on the research program that Dr. Benjamin has developed. Feasibility of the proposed program expansion to national prominence and multi-institutional collaborative mentorship is shown by funding and career development of current trainees at Duke and UNC, by trainees' publication track record (over 90 peer-reviewed articles with trainees as first author, and by the initial mentorship of young investigators from other institutions including Children's Mercy Hospital, University of Louisville, and University California-San Diego.